Michael Kimmel, a sociologist at Stony Brook (N.Y.) University, studies men for a living. He’s the author books like Misframing Men: The Politics of Contemporary Masculinities and Manhood In America: A Cultural History. More than anyone, Kimmel knows that Americans equate professional sports with toughness, grit, raw strength. “We proclaim our athletes to be the our most masculine humans,” says Kimmel. And team athletes, says Kimmel, are part of an intensely “homo-social” experience. “It’s this idea that team sports are physically, and emotionally, bonding,” says Kimmel. “The sports dynamic is not unlike the military. And like the military, there’s been this thought in sports that an openly-gay person would disturb this male-bonding element.”

Jason Collins is trying to shatter this thinking. As the first active male athlete to come out in major U.S. team sports, Collins is a crucial test. Assuming he gets an NBA job next year — at 34, Collins is an aging free agent — will his team embrace and accept him, and carry on as usual, to the point that pundits are breaking down his game, and not his sexuality, next season? Based on the overwhelming support of his peers — Dwyane Wade, Steve Nash, and many other players have fired off encouraging tweets, former coaches like Doc Rivers and Lawrence Frank lauded him — Collins should have no problem fitting in. “He’s a good dude,” says Washington Wizards center Emeka Okafor, who played with Collins in D.C. this season. “He’s got great character, a good sense of humor, he’s a good teammate and a hard worker. And in the NBA, that’s what we judge by. He’ll be accepted.”

If Okafor is right, that’s a huge victory for progress. “The truth is, there are few final frontiers for gay people in this country,” says Fred Sainz, VP for communications and marketing for the Human Rights Campaign. “Male professional sports is the last bastion.”

It’s hard to understate Collins’ impact. “By doing what he did, Jason Collins has extended gay kids a lifeline,” says Sainz. “The message to that gay kid, even if he’s not involved in athletics, is reassuring. Even the jocks are gay. And there’s a message to bullies: gay kids are not second-class citizens. When young people hear negative stereotypes about gays, they think bullying is OK. It’s a vicious circle, and Jason Collins has cut right through the middle of it.”

Former NBA player John Amaechi, who came out of the closet in 2007 after this six-year NBA career ended, has seen Collins’ influence firsthand. In the two days after Collins’ announcement, Amaechi says he’s received over 250 message from young gay people around the world. “It’s amazing how resonant all the messages are,” Amaechi says. “They’re saying, ‘I feel safer and more hopeful because of what Jason has done. Not only that, but I feel safer and more hopeful because of the reaction that I’ve seen to what Jason has done.’ That is impact you can measure. I am indeed moved. I am proud.”

As an athlete, Collins has already drawn more Americans into the conversation about gay tolerance. “The guy who’s watching sports is not necessarily the guy who’s going to be the watching the CNN debate on marriage equality, or what SCOTUS is saying on marriage equality,” says NFL linebacker Brendon Ayanbadejo, an LGBT and marriage equality activist who won a Super Bowl with the Baltimore Ravens last year. “So now you’re going to be able to catch a different guy, and you’re bringing politics and social change into the sporting arena. It’s so important — with sports, you’re able to just cross different sections of America and talk about relevant issues.”

The consensus: Collins is the right man for the moment. “Collins could not be better suited to his new role if you auditioned a thousand people for it,” says Richard Rosendall, president of the Gay and Lesbian Activists Alliance of Washington, D.C. “He is poised, confident, strong, masculine, at ease with himself, and he’s known for being a tough player — a walking refutation of anti-gay stereotypes.”

Collins could alter many misperceptions. Not only that a gay player might be too “soft” to play in the NBA, but that testosterone fuels pro sports locker rooms, and that as a result, these locker rooms are inherently anti-homosexual. “Most people who have this fantasy about locker rooms, that they are this place of staunch machismo, haven’t spent much time in them,” says Amaechi. “The reality is that while there’s a lot of casual homophobia pretty much everywhere, the sort of overt homophobia that I sort of experienced when I played — people talking about gay people in an incredibly derogatory way — is just less prevalent. And it’s because of the kinds of lives that these athletes lead, where they are now involved in the film and music industry, involved in art and fashion. It has just broadened their minds a bit.”

Okafor, the Washington Wizards center, says his teammates have already discussed the possibility of an openly gay player. “We just have broader minds now,” says Okafor. “The subject matter has come up. Sometimes we talk – ‘hey, man, what are the odds of you having a gay teammate? Would you be ok with it?’ A lot of times, people are like, ‘yeah, we’ll be fine. We’ll be absolutely fine.'”

And as for this naive thought that straight athletes won’t want to shower or undress next to gay teammate, for fear of being “checked out” all the time? “Anybody who thinks that the professional sports locker room is some sort of sexual playpen is living out perhaps their own alternative fantasy,” says Amaechi. “The reality is it’s a workplace. The main concern for me and most of my teammates when I played, was can we get a shower and get dressed in some privacy before the media comes in.”

“In the locker rooms and shower, it’s very loose,” says Okafor. “You’re not thinking this guy is checking me out or whatever. Since you spend so much time around your teammates, they’re pretty much life family, and around family, anything goes. You’re comfortable. You can be yourself.”

Not that Collins shouldn’t expect some needling. “You have to have some thick skin,” says Ayanbadejo. “It’s not going to be easy. They’re going to rib you a lot.” Ayanbadejo took his share of ribbing in the Ravens locker room this season. “Terrell Suggs was on me all the time this year, calling me the gay ambassador,” says Ayanbadejo. “He rode me and rode me. But the then he pulled me aside and said, ‘you know, BA, I voted for marriage quality in Maryland. I thought it was the right thing to do.'”

In a way, such banter is a true sign of progress. “It totally is, because not only can we joke about it, you’re not going to take yourself too seriously,” says Ayanbadejo. “But you know, guys are going to make fun of you, just like a family would make fun of each other. But when it comes down to it, when it comes down to that moment when either you’re with me or you’re against me, guys are going to be with you. And that’s a beautiful thing to see.”

To Amaechi, the support that Collins has received has been encouraging. But at the same time, he says, it’s just a start. “If people are really interested in not just making this a media moment, don’t just like Jason on Facebook,” says Amaechi. “Don’t just follow him on Twitter and pat him on the back when you see him. The next time someone stands up and talks about how there needs to be a law to keep gay people out of schools, that it’s OK for gay people to be fired for their sexuality, that their relationships shouldn’t be recognized, that’s when you show your commitment. That’s how Jason Collins will have a bigger impact than anyone ever imagined.”